Hey guys,
This is my first post on the forum, so please bear with me.

I've got a '98 F-150 supercab with the 4.6L V8. It's got the 4R70W tranny in it. 95K miles.

I've had a problem with the truck shuddering while slowing down at about 40 mph. I've never really noticed it doing it (well, maybe just barely) when driving along at 40 mph. It's most noticeable when coming to a fairly rapid stop from above 50 mph, and happens right at an indicated 40 mph every time. It's not a really rapid shudder, but more like a "loping" feeling in the back of the truck. Maybe a 2 hz cycle?? I've ruled out rear brakes by having the drums turned.

I did some searching here and thought it might be the torque convertor shudder that everyone talks about, so I changed the fluid and filter (both pan and torque convertor) and added back 11.5 quarts of AAMCO Mercon V tranny fluid.

I've driven maybe 100 miles or so since then, and the problem still seems to be present.

I happened to be driving by the local AAMCO tranny store today in my other vehicle, so I swung in and just asked them about it. They said it did not sound like a torque convertor problem, but that it could be pretty bad. I told him it couldn't be too bad, since it had been doing it for at least 30K miles (maybe even 40K). He said to bring it by and they would drive it, but I'm not sure I want to turn a shop loose on it if is something I could fix for myself.

Any thoughts would be welcome.

thanks